WASHINGTON (AP) - Secretary of State Hillary Rodham Clinton and the nation's top military leaders pleaded Wednesday for Senate approval of a long-spurned high seas treaty, arguing that the pact will boost U.S. national security and create much-needed American jobs.

In a rare joint appearance before Congress, Clinton, Defense Secretary Leon Panetta and the chairman of the Joint Chiefs of Staff, Army Gen. Martin Dempsey, made the case for the U.N. Convention on the Law of the Sea, which was concluded in 1982 and has been in force since 1994. Republican opposition has stalled the pact for years and was on bold display at the hearing. The United States is the only major nation that has refused to sign the treaty, which has been endorsed by 161 countries and the European Union.

"We need to get off the sidelines and start taking advantage of the great deal that the Convention offers the United States and our business community," Clinton told the Senate Foreign Relations Committee.

In an impassioned plea, Clinton dismissed opposition to the pact as based on "ideology and mythology" and pointed out that the treaty has the backing of Republican and Democratic presidents, including former President George W. Bush; businesses, the energy and shipping industry and environmental groups.

She pointed out that U.S. oil and gas companies now have the technology to explore the extended continental shelf, which could be more than one and half the size of Texas and rich in resources. Those companies, however, are seeking the greatest legal certainty from the treaty before investing millions.

Point by point, she refuted the criticism of the treaty, such as concerns that it is a U.N. pact.

"That means the black helicopters are on their way," she said of the unfounded fear.

She pleaded with lawmakers to listen to businesses, the U.S. Chamber of Commerce and the military, strong proponents of the pact. "The cost of not joining is increasing," she said.

Military leaders past and present contend that the treaty would strengthen U.S. naval power, giving Americans favorable navigational rights and the freedom to use military force, if necessary. Among those are the right of transit through international straits and the right of passage through foreign territorial seas.

"Joining the convention would provide us another way to stave off conflict with less risk of escalation," Dempsey told the committee.

Panetta pointed out that the United States has one of the longest coastlines, the largest extended continental shelf and has more to gain from approval of the treaty than any other country.

"If we are not at the table, then who will defend our interests?" Panetta asked.

The treaty has languished for years due to opposition from those who say it would undermine U.S. sovereignty, and in recent months challenges from tea party Republicans. Sen. John Kerry, D-Mass., chairman of the Foreign Relations Committee, acknowledged the difficulty in moving the treaty, especially in an election year. He announced at the start of the hearing that he would not push for a Senate vote before the November elections.

But he insisted that approval of the treaty is necessary because the United States "has lived by the rules, but we don't shape the rules."

Kerry cast the issue in terms of the U.S. losing out to growing military powers China and Russia, which is claiming oil and other resources in the Arctic.

The treaty has exposed divisions within the Republican Party. Pro-business groups led by the Chamber strongly support ratification of the pact while tea partyers argue against it. The fracture was evident last week when House Republicans, ignoring the pleas of the Chamber, voted to limit funds for enforcement of the treaty as part of a far-reaching defense bill.

Conservative Republicans expressed the strongest opposition to the pact, arguing that it would force the United States to redistribute wealth through royalties from offshore drilling and impose regulations on greenhouse gases.

"This treaty would subordinate American sovereignty to the United Nations, impose an international tax on U.S. energy production that would raise costs for American families, and act as a backdoor Kyoto Protocol that could allow foreign nations to regulate U.S. energy emissions," Sen. Jim DeMint, R-S.C., said in a statement.

Sen. Jim Risch, R-Idaho, said the high-seas treaty has "Kyoto written all over it."

Twenty-six Republican senators have signed a letter circulated by DeMint vowing to oppose the treaty if it gets to the Senate for a vote. The senators said in the letter that they are "particularly concerned that United States sovereignty could be subjugated in many areas" to an authority representing various countries.

"By its current terms, the Law of the Sea Convention encompasses economic and technology interests in the deep sea, redistribution of wealth from developed to undeveloped nations, freedom of navigation in the deep sea and exclusive economic zones which may impact maritime security, and environmental regulation over virtually all sources of pollution," the senators wrote.